#include <stdio.h>
#include <stdlib.h>

int main(void) {
    char S[10002];
    int sum = 0;
    int num = 0;
    int size = sizeof(S) / sizeof(S[0]);
    fgets(S, sizeof(S), stdin);
    for (int i = 0; i < size; i++) {
        if (S[i] == '\0') {break;}
        num = S[i] - '0';
        if (0 <= num && num <= 9) {
            sum += num;
        }
    }
    printf("%d\n", sum);

    return EXIT_SUCCESS;
}